Venoclysis equipment



Oct. 6, 1959 BURKE 2,907,325

vEN'ocLYsIs EQUIPMENT Filed Nov. 2'7, 1953 2 Sheets-Sheet 1 GEORGE K.BURKE ATTORNEYS Oct. 6, 1959 s. K. BURKE VENOCLYSIS EQUIPMENT 2Sheets-Sheet 2 Filed Nov. 27, 1953 GEORGE K. BURKE ATTORNEYS United mVENOCLYSIS EQUIPMENT ice 'Wh'en such additionalpressure is put on theliquid,

George Kenneth Burke, Bethlehem, Pa., assign'or to I Laros Company,Bethlehem, Pa.,

a corporation of Pennsylvania Application November 27, 1953, Serial No.394, s1-

This invention relates to improved venoclysis equipment. Moreparticularly, it relates to venoclysis equipment which can be used,without structural modification; for administering injection fluidsunder normal conditions and for rapid, forced injection o'rfeeding ofcontrolled:

. In administering injection fluids, such" as in the in-- increasedamounts of fluids in a given time period.

travenous injection of plasma 'or plasma substitutes or extenders, undernormal conditions the fluid is allowed to flow into the vein by gravityat a comparatively slow but steady, sustained rate. However, in cases ofemergency, it isnecessary to force copious amounts of the fluid into thevein,-as for instance when the patient has lost a large amount of blood.

The venoclysis equipment available heretofore consists of a length oftubing having a hypodermic cannula on one end thereof, the other endbeing adapted for insertion into or connection witha container for thefluid which is also providedwith an air inlet or so-called air-Waycannula. for introduction of the air-required to displace fluid in thecontainer and initiate flow thereof into "the tubing. .The device alsocomprises a slotted flow control member, in which the slot is graduatedand which is adjustable transversely of the tubing to vary thecrosstubing connected therewith, and the needle, are com-- pletelypurged of air, theneedle is inserted into the patients vein, and thefluid is allowed to flow bygravity into the vein.

As long as the conditions are such that the liquid flows into the, veinby gravity and it is not necessary to in crease the flow of the liquidinto the .vein to a greater degree than can be. elfected by adjusting.the position of the slotted member on the tubing, no great' problemarises.

The problems arise when it becomes necessary to force a substantiallyincreased amount of the liquid into. the vein during the feeding. Thiscan only-be accomplished by increasing the pressure on the liquid froman external source, that is by pumping air into the bottle or the likethrough the air-way cannula and upw'ardlythrouglr the shield surroundingthe cannula and terminating above the"; level of the liquid in thebottle. .When this is.done,1air may follow the liquid into the vein...This is extremely; 65

I cially when it .is read in conjunction dangerous, for as is known evena small amount of air in? jected intravenously is suff cient to inducesevere or;fatal air embolus. This is an everpresent hazard which ac-.vcounts for the attentive watch maintained during in.-':

travenous feeding when the pressure on the liquid in the bottle isincreased and the air or other gas pressuremay.

be so great that air can follow the liquid into the vein.

the pra'cticeis to withdraw the needle from the vein as soon as. thelevel of the liquid drops below the bottle mouth? Under those conditionsof increased pressure, there is also the possibility of air (or otherpressurizing gas)' being dissolved in "the liquid 'and'injected into thevein with it. v V

Despite'the maintenance of constant attendance, it is not infrequent forsevere or fatal embolism to develop in a matter of several seconds ifthere are air bubbles in the line and additional pressure is put on theliquid. The {practice is to watch for' the air bubbles and if any aredetected to, withdraw the needle immediately from the vein, purge thesupply line of the air, and reinsert the needle. Thisistime-consumingwhen time may be of the *essence in saving the patients life. Moreover,the repeatedinsertion of the needle is painful and may be dangerous.:Furthermore,-repeated purging of the tubing, after' it has been in use,results in loss of valuable fluid and, asthe purging is usuallyperformed, the fluid -is'spray'ed over the' floor and equipment of theroom Another disadvantage is that, after each purging, in ordertostart'the fluid flowing again, additional air must be introdu cedintothe. container. It is practically impossible at; avoid the introductionof contaminants with the air and these contaminants are not all removedby the usual filters such as those of cotton, when used under pressure.The known equipment also has the disadvan- Where the'patient is beingtreated, leading'to messy contage that back-flow of the'fluid, due tovenous pressure,

may cause interruption of the feeding and require removal andreinsertion of the needle with all the difliculties and hazards thatpresents. There is still another objection to be mentioned in connectionwith the venoclysis equipment currently in use. It is thisrif theinjection needle becomes obstructed, normal saline solution must beinjected into the tubing, adjacent the needle, to dislodge theobstruction. I

One object of this invention is to provide new and novel venoclysisequipment which can be used both for injecting fluid under normalconditions requiring the steady delivery, by gravity, of a relativelythin stream of the fluid, and under conditions where large amounts ofthe fluid must be injected rapidly without danger of entrain- -'-ment ofair in the liquid.

Another object is to provide equipment of the type stated in which theincreased amounts of fluid injected into the vein can be controlled veryreadily and administeredin a given time period which can bepredetermined.

A further object is-to provide transparent, disposable venoclysisequipment which can be readily deaerated before the feeding is commencedand iniwhich, thereafter, the existence of a partial vacuum reliably,prevents passage of air'wi'th the fluid to the needle.

A still fiurther object is to provide venoclysis equipment in whichback-flow due to venous pressure is relived as soon as'it develops. h

Another object is to provide equipment such that if an obstruction, suchas a venous clot, becomes lodged in the injection needle, it can bequickly dislodged by means of pressure exerted at the appropriate pointalong the length of the tubing.

'I.-'h es e, andother objects-and advantages will be apparent from thedetailed discussion which follows, espewith the attached drawing; inwhich-:-

Figure. l is a front elevation of invention,

Figure 2 is a sectional view taken on line 2-2 of Figure 1,

one embodiment of the 3 Figure 3 is a sectional view taken on line 3-3of Figure l, n H

Figure 4 is a sectional view taken on line 44 of Figure 1,

Figure 5 is a, top. plan view of a compressing device; Figure 6 is afront elevation. of; a modification of, the.

valve structureshown. inFigure L,

Figure 7 is a, front, elevation. of'another, modification,

a modification, shown.

ous channel for injection fluidflowing, by gravity from av source ofsupply to a. hypodermic cannula and.including, disposed along its lengthand. as, at least: in.- effect, an integral part thereof, a pump andcheck valve system for.

increasing the rateof flow. of. the fluid to the needle at;

will. The essential elements of the: new venocly sis equipment are a;drip tube, an. ohservationhousing enclosing: the drip tube and, havingan open bottom, checkvalves, a.

pump and. alength of tubing having across-section smaller than the pumpand adapted to receive on one end thereof-,

the hypodermic cannula, these. elements being interconnected in theorder named. to provide the continuous, channel and the pump-beingcompressible, preferably manually, transversely of. thelongitudinal axisof, the equip-- ment, to actuate the check valves, thereby interrupting,

flow of the fluid to the. pump and forcing the fluid into. the needle. p

In, the preferred embodimenh the equipment is made.

wholly, of transparent plastic, material. Since it. is preferred to havethe drip tube, observation housing, and valves relatively rigid, whilethe narrow tubing feeding directly to the needle is preferably moreflexible and resilient to allow for thenecessary play. when, the needle.

is inserted in the vein, and the pump must be compressible transverselyof the axis of the. equipment and suflicient-ly resilient to rapidlyreturn to normal expanded. condition when: the compressing force isremoved, it may be desirable, to moldthe parts separately, fromditferent plastic materials, and to join them together to form thecontinuous channel for the needle-by meansof relatively rigid plasticadaptors. and short lengths or couplings; of;

the more flexible, tubing' Throughout, the plastic ma terial must beeffectively resistant to the, chemicalaction, of any of the fluids whichwould ordinarily be conducted therein in connection with, intravenousand like injec:

tions and capable of withstanding heat or cold sterilizertron withoutdamage or: any noticeable softening, It,

should also be a material which can be. produced in the form of tubinghaving smooth innerand outer surfacesand a high degree of uniformity"in. respect, to its internal. and external diameters.

Polystyrene is tough, transparent, relatively rigid, and. may be used toform the: drip tube, observation housing,

check valves and adaptors. Other materials which meet.

the requirements may be used, however. For the more flexible, narrowtubing and the compressible pump,.plasticized polyvinyl chloride (whichsho uld preferably have, a limited lead content not greater than 15parts of lead/million) iseminently satisfactory, but other therm'o Theinvention is, not limr' ited to use of any particular transparentplastic materials plastics may be found. useful;

having the properties' mentioned,-- and is contemplated that all partsof the equipment may be molded of the same plastic material: ina;si:ngle molding operation:

Referring now to Figure 1, there is shown a-hottle-z the lower endofrwhich is provided with a metal band 3 to which is pivotally connecteda wire bail 4 hywhicli the bottle 2 carrbe; mounted: for use in invertedposition upon a support, asupon the hook 5; The bottle disthe drip tube6 in the observation tube or housing 7. The tubular adaptor, drip tube6, and the observation tube 7 are made of clear, transparent polystyreneso that the dropwise discharge of the fluid into the housing 7 can beobserved. The bottle is normally sealed with a puncturable seal,preferably of-asoft material adapted to substantially close a. punctureafter the puncturing instrument is withdrawn, and the forward end of thebottle adaptor, which is preferably pointed or beveled,renderingitneedle-like to facilitate puncturing of the seal thereby,extends upwardly through the seal into the fluidin .the bottle. Thebottle; is provided with the. usual air-way cannula 6a surrounded by ashield 6b which extends upwardly through the bottle to a point above thelevel of the liquid when the bottle is in the inverted position.

The observation tube; 7 is. connected with check valve 8,: pump 9.,check valve 10, and the length of narrow flexible tubing 11 havingneedle; llmounted onsleeve: 13 supported on, the rearward or lower end;thereof, through aseries. of hollow adaptors 14,. 15,,16, 1-7, 18,19,and 20 ..and relatively shortlengths. or couplings of flexible tub-., 25

ing-Z1,,22, and ZBint TWhichthe-ends of the. adaptors ofredueeddiameter, project-,,-to3provide acontinuouszchannel through:which the-fluidflows'from, the bottle 2' to, theneedle 12. v 1

Adaptors. 1'5'and 16,. associated, with. the. tubular morn-- ber. 24,constitute the chechvalve- 8, the. adaptorslS and. 16being, theinletandoutletcof the; valve, respectively... Enclosed by the adaptorsand; member; 2.4,. and; as shown. in. moredetail in Figure 3., is; a-.seamless; check ball 25 ofsoft, resilient.material,v suchas surgicalrubber or plas- IiG.WhlCh,-il1, normal; use: of the. equipment, floatsin the fluid and is: restrained in its. downward movement by the lugs.vZ6 projecting; inwardly from. the internal wall. of member 2.4; sothatpassage. of the fluidthrough the equip-- .:ment is; not impeded;thereby. Adaptors. 19=an l 20, to-

gether with tubular member 28,: constitute the check valve 10 The. valvecomprises the seamless check ball 29 of soft resilient material: such.as surgicalv rubber-or plastic. 111::the normal; use of the equipment,ball: 29 floats inthe fluid; passing, through the valve and isrestrained in. itsdownwardg, movement by lugs or restraining membersprojecting inwardly.- from the inner wall ofv member 28- so-thatithe,channelin adaptor 20 remains open for corn tinuous gravity flow of thefluid into the tubing 11. The restraining; members. may be of atype suchthat those members, function asfilters forthe liquid passing throughth.e -.valve From the valve. 10, through adaptor 20 forming the outlet;thereof, the. fluid passesinto. the narrow flexible tubing 11 (shownbroken in Figure l) which may be of any suitable length but is. usuallyquite long, and thence into the needle. Instead of supporting: the.needle directlyon-the plastic tubing, an intervening cuff ofsoftresilient material; preferably surgicalw rubber, may beprovidedwhen, as; issometimes the case, it is desirable or necessary toinject, periodically, a second diiferent fluid intothe veinsimultaneously. with: the fluid flowing from bGItleLZLf in. the. deviceillustrated, the tubularbottle adaptor, dijp; tube, observationhousing,valves, and adaptors were all;- molded from polystyrene, while the.pump, flexible couplings. and, tubing 11 were extrusion molded fromplasticized: polyvinylchloride. When these two; plasticsaresheldrintcontaet with each'other, thereis a tendency tolchemi'calreaction which-may involve plasticizers presenti 'In 'thi's instance, orin the 'caseof any other two materials fromwhich the respectiveparts-may be molded whenrthere is a: likelihood of chemical reactiontaking place,-,and-'-such' chemical reactionisnot desired, the innersurface of the tubing, or theoutersurfacesof'theadaptors, over'theiareaof contact between the surfaces, may

be coated with' aliquid substance or composition'which, on drying formsan inert barrier between the surfaces whereby the chemical reaction isprevented. In the em,- bodiment illustrated, the outer surfaces of thepolystyrene parts which would normally contact with plasticizedpolyvinyl chloride were coated with'the commercially available productLogaquaint (a transparent or ambercolored resinous liquid having a flashpoint of 120 F. at 7.6 lbs. solids/gal.). Other eflective barriersubstances may be used. After drying of the barrier coating or film, theends of the couplings, and the end of tubing 11, may be spread in anysuitable way, the reduced ends of the adaptors fitted therein, and thespreader removed so that the'tubing grips the coated portion of theadaptor to hold the latter firmly in position in the tubing.

The polystyrene adaptors may be cemented. to the observation housing andtubular members 24 and 28, by means of any suitable plastic cement.

The equipment comprises the usual flow control means in the form of aplate-like member 30 made of sheet metal, aluminum or the like andprovided with tapering slot 31 through which the narrow flexible tubing11 passes. By adjusting the slotted member 30 transversely of the tube,the tube is more or less closed as it is moved into the narrow endportion of the slot thereby to resist the flow of the fluid. At thewider end of the slot, which is at least slightly smaller than theoutside diameter of tubing 11, the latter will be compressedsuificiently to cause the flow control member 30 to be eflfectively heldin place on the tube by the resiliency or expansivepressure of the tube.Gauge marks may be provided on member30 for indicating the settingthereof; The slotted member 30 is shown in perspective in Figure 4. i

There is also shown in Figure 1'(and in detail in the top plan sectionalview of Figure 5) a clamp generally designated 32 and comprising legs33, 34 pivoted at 35, and joined, adjacent their free ends, by a steelcompression spring 36, at least one end of the spring being providedwith means for securing and detaching it from one of the legs. As shown,the spring is detachably secured to legs 33 and 34 by hook and eyearrangements. The clamp is disposed between bosses 38, 39 moldedintegrally with the pump 9 and held in position on the pump by thebosses and is provided with the extensions 33a, 34a which may be heldbetween the fingers for facilitating compression of the spring and,

indirectly, of the pump. The provision of clamp 32, or of any equivalentcompressing device, is entirely 0ptional and in most cases is usuallydispensed with. However, it may be provided to insure proper compressionof the pump 9 when the latter is of such rigidity that it is not readilycompressible manually. It may be easier in some cases for a femalenurse, for instance, to compress the tube by pressing the legs of theclamp together adjacent their free ends and then releasing the pressureon=the legs to allow the spring to return to its normal expanded state.

'Pump 9 may have any suitable length, has a crosssection greater thanthe'cross-section of tubing 11, and usually at least twice as great, andpreferably has a re- 'siliency and wall thickness such that it ismanually compressible to bring the opposite sides of the tubing formingit together or closer together for the purposes set forth below.

When the equipment is set up as shown, and pump 9 is inthe normalexpanded condition, the flow of the fluid from bottle 2 being initiated,and balls 25 and 29 being afloat in the fluid in valves 8 and 10, thefluid will flow by gravity from bottle 2 downwardly through thecontinuous channel formed by the interconnecting hollow or tubularpartsto the needle 12 and thence into the vein at a comparatively slowrate controlled by the position of the slotted member 39, and in theform of a""6omparatively'thin stream. However, when pump 9 iscompressed, as by grasping itin the handand press= ing the oppositesides of the cylindrical wall together, while the fluid is flowing fromthe observation housing.

or tube 7, and a constant level of the fluid is maintained inobservation housing 7, ball 25 rises into the rearward or lower,slightly outwardly flaring, end of the centrally disposed channel inhollow adaptor 15, which functions as a valve seat, and as soon as thecompressing forceis applied the flow of the liquid from the observationtube or housing is cut ofi. When the pressure is removed and thetubular'pump 9 returns to its normal expanded condition, ball 25 isunseated and the system is again open. As a result of the pumping actionthus created by compression and expansion ofthe tubular pump, the fluidis forced to flow into the needle at accelerated rate. A seriesofalternate compressions and expansions of the compressible pumpwill,therefore, deliver a series of increased doses of the injection fluidinto the vein whenever such increased doses are required. i

An outstanding advantage of this novel equipment is that, as will beapparent, it can be used for both normal administration of the fluid bygravity flow andforforced injection of relatively copious amountsthereof at will, without requiring the use of an extraneous air pump inconnection with the equipment. That is, it ,is not necessary to forceair through the air-way cannula in order 'to increase the quantity .ofliquid introduced ,into the'vein. Moreover, the exact'amount of liquid;forced into the vein, as a result of each compression and expansion ofpump 9 is determined by the cross-section and length of the pump and theextent to which it is compressed, that is whether the opposite walls arebrought more or less closer together by the compressing force exertedthereon. The quantity of fluid forced into the vein by each successivecompression of the pump is therefore fixed by the dimensions of the pumpand, being once impirically determined for the dimensions of a pump ofgiven cross-section and length, the number of compressions required toforce a given totalquantity of fluid into the vein in a given period oftime can be predetermined and the equipment can be marketed with exactinstructions for the physician or nurse in this respect For example, ifpump 9 comprises a tube 5" long and A" in cross-section, each fullcompres-' ond intervals. The equipment has been used to accomplish theforced intravenous feeding or injection of dlinical dextran which has aviscosity as high as any solution which is apt to be intravenouslyinjected. Actually, it is found that the viscosity of the fluid does notnoticeably effect the number of compressions of the pump required toforce a given amount of the fluid into the vein and therefore theinstructions issued with the equipment are of general application andvalid for various types of parenteral injection fluids including glucosesolutions, solutions of amino acids and other nutrients,

solutions of antibiotics, such as solutions of penicillin, solutions ofliver extract, and other solutions which may be injected safely into thevein.

Pump 9 desirably has a cross-section at least twice the cross-section oftubing 11, the latterusually having a cross-section of to 4,". Pump 9may have a crosssection of from :5 to 2" and a length of, say, 3" to 6",or it may be even longer than 6".

The equipment shown in Figure 1 may be modified in various ways. Asalready stated, clamp 32 may be omitted, and if so, the raised portionsor bosses on the external wall of 'pump 9 may also be omitted.

In a variation. or modification, when a clamp such as. clamp 32 isprovided, it may comprise an adjustable set screw'forlimiting the extentto whichv the spring is compressed so that .a partial compression of thepumpcan be reliably obtained if that, is desired. Also, the check.valves 8 and 1-0; which are. identical and one of which is showninsect-ional detaiLin Figure 3; maybe replaced byother suitabletypes-ofcheck valve, such as thatshown in- Figure- 6 in which there isshown the tubular. mem-. ber- 40 cemented, at its opposite ends, to theadaptors 41' and 42 ('shown broken away); and enclosing valve member 43which reciprocates. in the direction of the of the tubing and isprovided with a chamfered surface, as'shown at 44, adapted to be seatedin the slightly flaring end of the channel in the respective adaptors.

If back-flow due to venous pressure or suction develops in theequipment, the ball 29 will rise and be seated in the channel of adaptor19, thus interrupting the flow of the liquid until the back-flow iscorrected; It will be apparent that, if desired, valve 28 may beomitted.

The new equipment may be used with bottles of types. other than the oneshown, which, as marketed, is provided with a seal puncturable by thebottle adaptor aligned with the drip tube 6 and forming an integral partof the equipment. Not all suppliers of intravenous in jcction liquidsutilize bottles of that type. Thus, in somejcases, the liquid is put upin a bottle of the screwcap type and without a seal closing the mouththereofi.

The present equipment may be used with bottles of the last-mentionedtype by providing a stopper, such as a rubber stopper, adapted to fitinto the mouth of the bottle and provided with channels extendinglongitudinally thereof and into which, respectively, the bottle adaptoraligned with the drip tube 6, and the air-way cannula and shieldtherefor may be inserted. Such an arrangement is shown in Figure 7', inwhich bottle 45 of screwcap type (shown broken away) is provided with arubber stopper or gasket 46 having channels forreceiving the bottleadaptor 47 and the air-way cannula and shield or air-way tube designatedas 47a. The stopper may have any desired diameter, depending on thediameter of the bottle mouth, and may be marketed separately from theequipment or in assembly therewith, e.g., pressfitted on the bottleadaptor. It may be, and preferably is, marketed as a separate item butwith the shield for the air-way cannula inserted therein so that, inassembling the equipment, it is unnecessary for the nurse or doctor totouch the shield which, in use, extends through the injection liquid.Stoppers of 'the kind shaped in a mold adapted to leave a thin layer ofthe rubber in the form of a readily puncturable diaphragm over the endsof the channels which serve as the inlet ends when the device is in useare preferably employed, the bottle adaptor and air-way cannula. beingpushed through the diaphragms into position in the stopper.

As shown in Figure 8, the drip tube 48 may be branched, as. at 49 and50, each of the branches being adapted to project into a bottle orcontainer and receive a diiferent injection fluid from it. As shown, thebottles 51, 52 are tilted so that the. fluid from each flows smoothlyinto the drip tube.

In Figures 9 and there is shown a modified pump and valve arrangement inwhich the check valves 53, 54 are, at least in effect, integral parts ofthe compressible tubular pump 55, and connected withthe remainingelements of the equipment through adaptors 56, 57, respectively, andsuitable couplings.

The balls 58' 311(1159 are inserted in the valves 53, 54,

respectively, the latter are fitted into the opposite ends' of thetubular pump 55, and may be cemented to the pump.

Inresponse to lateral compression of tube 55, the balls 58 and 59" ofthe valves function in the same manner as the balls 25, 29' of theequipment of Figure. l, but are restrained in their downward movement bythe disk-like members 60, 61 press-fitted'in the flanges (indicated. by,n m r l 62 i1'63. e p c ly). on. he inn r; all of; tubeSfS. Thedisk-like members 60,61 may beoffa type such that they alsoserve, asfilters for the liquid; The restraining. disks, 6Q 61; (one of which,60, is shown in the sectional top plan view of Figure 10); may beformedl of surgical rubber or suitable plastic material such as nylon,Dacronfi polystyrene or theliker Suitable filtersmay be provided atappropriate places. As previously mentioned, the re.-' straining.members injthe. valves of Figures 1 and. 3., and

in the equipment.

the. disksofi'FigureS 9. and 10 may be of types. that serve.

the additional. purpose of filtering theliquid, The reel strainingmembers or disks may be of fibrous character and formed, for example, ofcotton, nylon, regenerated cellulose and the like. They may be formedfrom woven fabrics comprising spun yarns arranged so that the ends.

of. the short. or staple fibers projecting from the spun yarnsinter-meshto form sinuous channels which mean-.

normal gravity flow, and for the forced administration. of the fluidrapidly and incontrolled amounts in a. given.

period of; time as. may be required without requiring; the use. .of anextraneous airpump.

conventional equipment. Itcan be effectively evacuated by means. of thepump before theneedle is injected, the air which is. forced'upwardly inthe direction ofthe bottle leaving the latter through the air-waycannula.

Once the liquid is flowing in the device and has passedthe first checkvalve, a partial vacuum exists in the.

system and it is. impossible for air to. become entrained.

inv the liquid. Since the. pressure of the air on. the.

liquid and the venous. pressure are in equilibrium, and; any disturbancethereof is immediately corrected by the;

action of. the second. valve, the danger of accidentally injecting airinto the vein, and of resulting air embolus,

is entirely eliminated. It also. eliminates the danger.

of introducing air-borne. contaminants into the vein and.

will assist in preventing the incidence of hepatitis when; plasmaisinjected. Other advantages are that the pump, valves, and other partsconstitute a single unit for the.-

combined purposes of normal and forced injection or;

feeding, no accessory equipment or devices such as aseparate, portableair pump being needed, the unitis,

disposable, therate of transfusion is clearly visible along: the entire.length of the preferred embodiment of; the, equipment, the latter iscompact and may be packaged separately or as a unit with the injectionfluid, it is;

relatively light in weight and easily transportable, it may be packedsterile, for instance as av standard item of the physicians. orambulance kit, it can be put into;

use quickly under emergency conditions, as in time. of

war, without technical difiiculties, none of the. parts is breakablewhen, as is preferred, the essential elements of the equipment are madeof tough plastic; material, reverse flow or back-pressure is eliminated,and. if the needle is-obstructed, as by a venous clot, the obstructioncan be immediately dislodged by a slight compression of the pump, justsuflicient to increase the fluid flow and-dislodge the obstruction.

Although it is preferred toform all of the essential parts of theequipment" of clear, transparent and tough plastic, certain partsthereof, such as the drip. tube and observation housing, may be made of,glass, if desired.

In addition; the; equipment entirely lacks the major disadvantages.ofthe It will be understood, ofcours eQthatthe relative proportionsofthe check ValVe orLt he and the end of the channels in the respectiveadaptors which serve to seat the balls is such that the valve is seatedpromptly to close oi the supply of fluid immediately on compression ofthe pump, or to relieve back-flow as soon as it develops. The check ballshould be light inweight and responsive to the pressure of the fluid.Further, the tubular members comprising the valves are preferablysmaller in cross-section than the-pump and relatively short as comparedto the pump and the check ball is also small, the channels in theadaptors in which the balls are seated being flared outwardly to thedegree necessary to permit ready closing of the channel, at the mouththereof, by the balls when the latter are moved into the mouth of thechannels as a result of compression of the pump or by back pressuretending to induce back-flow in the equipment. It will be understood thatthe pump may have diiferent shapes and may be, for example, a ball-typepump.

Since all of these various modifications in details may be made withoutdeparting from the scope of this disclosure, or of the invention, it isto be understood that it is not intended to limit the invention exceptas defined in the appended claims.

I claim:

1. Venoclysis equipment formed of plastic material substantially all ofwhich is transparent and adapted normally to provide a continuouschannel for injecting a fluid flowing from a source of supply to ahypodermic cannula, said equipment comprising in combination a driptube, a housing for the drip tube, and a length of tubing of relativelysmall cross section adapted to receive the cannula at one end thereofand including disposed along its length below the drip tube and abovethe end of the tubing of relatively small cross section removed from thecannula receiving end, and as, at least in effect, an integral part ofthe equipment, a tubular pump compressible transversely of the axis ofthe equipment and readily returnable to normally expanded condition andrelease of the compressing force, said equipment including a valveelement and a valve seat element for said valve element operable toclose the inlet into the pump when the pump is compressed.

2. Venoclysis equipment formed of transparent plastic material andadapted normally to provide a continuous channel for injection fluidflowing from a source of supply to a hypodermic cannula, said equipmentcomprising, in combination, a drip tube, a housing for the drip tube,and a length of tubing of relatively small cross-section adapted toreceive the cannula at one end thereof, and including, disposed alongits length, between the housing for the drip tube and the end of thetubing of relatively small cross-section removed from thecannula-receiving end, and as, at least in effect, an integral part ofthe equipment, a pump and check valve system, the pump being tubular,compressible transversely of the axis of the equipment and readilyreturnable to normal expanded condition on release of the compressingforce.

3. Venoclysis equipment in accordance with claim 2, characterized inthat the drip tube and the observation tube are formed of relativelyrigid plastic material and the pump and cannula-supporting tubing areformed of more flexible and resilient plastic material.

4. Venoclysis equipment formed of transparent plastic material andadapted normally to provide a continuous channel for injection fluidflowing from a source of supply to a hypodermic cannula, the equipmentcomprising, in combination, a drip tube, a housing for the drip tube,and a length of tubing of relatively small cross-section adapted toreceive the cannula at one end thereof, and including, disposed alongitslength, between the housing for the drip tube and the end of thetubing of. relatively small vcroiss-sectio ernd u cannula receiving end,and as, at least in eflec gral part of the equipment, a pump and checkvalve system, the pump being formed of plasticized polyvinyl chloride,and being compressible transversely ofrthe axis of the equipment andreadily returnable, to normal expanded condition on release of thecompressing force.

' 5. Venoclysis equipment formed of transparent'plastic material andadapted normally to provide a continuous channel for injectionfluidflowing from a source of supply to a hypodermic cannula, theequipment comprising, in combination,'a driptube, a housing forth'e driptube, and a length of tubing of relatively small cross-section adaptedto receive the cannulaat one end thereof and including, disposed alongits length, between the housing for the drip tube and the end of thetubing of relatively small cross-section removed from thecannula-receiving end, and as, at least in effect, an integral part ofthe equipment, a pump and check valve system, the pump being a tubularmember of predetermined length and cross-section, compressibletransversely of the axis of the equipment, and readily returnable tonormal expanded condition on release of the compressing force.

6. Venoclysis equipment according to claim 5 char- .acterized in thatthe predetermined cross-section of the of the observation tube, atubular pump of relatively large cross-section and having an inlet andan outlet, the inlet being connected with the outlet of the check valve,a second check valve having an inlet and an outlet, the inlet beingconnected with the outlet of the pump, and a length of tubing ofrelatively small crosssection and one end of which is connected with theoutlet of the second check valve and the other end of which is adaptedto receive the cannula, said tubular pump being compressibletransversely of the axis of the equipment and readily returnable tonormal expanded condition on release of the compressing force.

8. Venoclysis equipment adapted normally to provide a continuous channelfor injection fluid flowing from a source of supply to a hypodermiccannula and comprising a drip tube, an observation tube enclosing thedrip tube and open at the bottom, a check valve having an inlet and anoutlet, the inlet being connected with the bottom of the observationtube, a tubular pump of relatively large cross-section and having aninlet and an outlet, the inlet being connected with the outlet of thecheck valve, and a length of tubing of relatively small cross-sectionand one end of which is connected with the outlet of the tubular pumpand the other end of which is adapted to receive the cannula, saidtubular pump being compressible transversely of the axis of theequipment and readily returnable to normal expanded condition on releaseof the compressing force.

9. Venocylsis equipment adapted normally to provide a continuous channelfor injection fluid flowing from asource of supply to a hypodermiccannula and comprising a drip tube, an observation tube enclosing thedrip tube and open at the bottom, a tubular member of relatively largecross-section and having a check valve forming an integral part thereofat each of its opposite ends, the forward check valve having an inletconnected to the bottom of the observation tube and the rearward checkvalve having an outlet connected to a length of tubing of relativelysmall cross-section and adapted to receive the cannula on the free endthereof, said tubular member having the check valves directly associatedtherewith consitituting a pump Compressible transversely of the (ifthe'equipment and readily returnable to, normalj'expanded 'cqndition onrelease of the compressing to e.

Tenney Nov. 21, 19 16. Brokaw Feb. 13', 191 7 Heir Sept. 15, I925Ravenscroft, et-ral Sept. 10, 1940;.

- 12 Sehwab V Apr. 22, 1941 Abbgtt" Jan. 16,- 1951 Cutter July-7; 1953;}Butler Mar. 16; 1954 Dennis Y Apr. 6; 1954' Ryaniet a1; June-22; 1954;

OTHER REFERENCES I Fischer et al.: Successful Experimental Maintenance:10 of,Life; Annals of Surgery,,ve 1.. 136, No. 3, September 1952, pages415-484., page 478. relied on, in- Scienee Library.)

(Available, 4

